This invention relates to the method of making a colored metal decorative panel, and more particularly to a partly colored decorative panel which is prepared by impressing sublimable dyes by sublimation transcription on the surface of a synthetic resin layer electrically deposited on the surface of etched concave portions of a metal plate.
A known method of coloring a metal plate, particularly, a stainless steel plate is based on oxidation or ordinary printing. Oxidation coloring has the merit that since a metal surface is colored by oxidation, the gloss of a metal plate itself can be favorably utilized, but is accompanied with the drawbacks that a pattern layer produced has a low resistance to acids. Since coloration is applied on convex surface portions or those surface portions which are flush with the other surface portions which should not be colored, a picture layer produced is likely to be faded away by contact with external objects or by being abraded thereby. On the other hand, coloration of a metal surface by ordinary printing has the drawback that dyes used often have a low adhesivity to a metal, and prove indurable. Where dyes are applied only in the concave surface portions of a metal plate, then the dyes will remain more durable. However, the ordinary painting or printing method presents difficulties in applying dyes only to the concave surface portions of a metal plate in accurate conformity thereto.
Another metal surface-coloring method disclosed in Japanese patent publication No. 51734, 1972 comprises the steps of first coating a synthetic resin layer on, for example, a metal plate and then coloring said resin layer. This method still had the drawbacks that a synthetic resin layer was found to have low adhesivity to a metal plate; and since the synthetic resin layer was deposited all over the surface of a metal plate, it was impossible to effectively utilize the gloss of metal plate, imposing great limitations on the designing of a picture pattern.